I don't want to sound like a snub, because I am not.
But if you go through the trouble to buy a suit (you know the deal that the pants and a jacket are made from the same fabric, color and pattern), and make sure it fit (a lot of people skip this part), then why not actually wear a pair of shoes that are half way decent, not made completely from petroleum byproducts (tree hugger/animal activist will have some issues here, then again, tree huggers don't wear suits). Even an expensive, nicely tailored suit with good fabric will look cheap and fucked up if it is worn with a pair of cheap, fucked up shoes. If you are going to make the effort to look presentable, why not go all the way and look good?
I hope I will never have to buy and wear a suit; but if it ever happens, you bet you money I will buy some decent shoes.